BEIRUT, Dec 15 (Reuters) - The Lebanese army said on Wednesday it had discovered two sophisticated Israeli surveillance devices in mountains above Beirut which could have helped Israel to monitor and target sites for attack.

The equipment was discovered using information passed to Lebanese intelligence by resistance sources, it said in a statement, referring to the militant Shi'ite group Hezbollah.

The army said Israel had planted the devices in Sanin and Barouk, mountain districts respectively to the north and south of the capital.

They could establish coordinates of targets and included lasers capable of reaching 20 km (12 miles) away, an independent power supply and equipment to transmit pictures.

One military source said the equipment dismantled on Wednesday could also have monitored a large swathe of Lebanon's border region with neighbouring Syria.

Pictures released on the army's website (www.lebarmy.gov.lb) appeared to show devices partly covered by stones on the slopes of rocky hills.

Shortly after the army announcement Israeli warplanes flew at low altitude over towns in south Lebanon, residents said.

But the Israeli army issued a statement saying there is no unusual (military) activity in the area.

Two weeks ago Lebanon said Israel had remotely detonated two communications monitoring devices it had planted in the south of the country. (Additional reporting by Ori Lewis in Jerusalem; Editing by David Stamp)